Expression of a synthetic cry1EC gene for resistance against Spodoptera litura in transgenic peanut (Arachis hypogaea L.)

Abstract

The tobacco cutworm (Spodoptera litura) is a polyphagous foliage insect and a major pest on peanut (Arachis hypogaea L.). S. litura is susceptible to the chimeric δ-endotoxin Cry1EC reported earlier. De-embryonated cotyledon explants of peanut were transformed using Agrobacterium tumefaciens strain EHA101 harboring a synthetic cry1EC gene driven by the CaMV 35S promoter. Transgenic plants of peanut with a single copy insertion of cry1EC were selected in the T₀ generation by Southern blot hybridization. Real-time PCR, Western blot and ELISA analysis indicated that expression of the cry1EC gene was higher in single copy T₁ plants. Immunoassay showed expression of Cry1EC up to 0.13% of total soluble protein in T1 plants. Leaf feeding bioassay on highly expressing transgenic lines showed 100% killing of larvae at the 2^nd instar stage of S. litura. This is the first report of transgenic peanut plants with resistance to S. litura.